Market adoption of wireless LAN (WLAN) technology has exploded, as users from a wide range of backgrounds and vertical industries have brought this technology into their homes, offices, and increasingly into the public air space. This inflection point has highlighted not only the limitations of earlier-generation systems, but also the changing role that WLAN technology now plays in people's work and lifestyles across the globe. Indeed, WLANs are rapidly changing from convenience networks to business-critical networks. Increasingly users are depending on WLANs to improve the timeliness and productivity of their communications and applications, and in doing so, require greater visibility, security, management, and performance from their networks.
Dynamic Frequency Selection (DFS) requirements give radar priority in wireless mesh network channels operating in the 5 GHz range. When a given wireless mesh node detects a radar signal on a given DFS channel, the wireless mesh node is required to move off that channel. In a mesh network not all mesh nodes may see particular radar signals, and therefore any detection of a radar signal needs to be signaled throughout the mesh network. Further, rather than stopping the use of a DFS channel when a mesh node detects radar, a DFS mechanism should trigger the mesh node to change channels to one that is known to be free of radar signals. One of the main advantages of mesh networks is their ability to re-configure themselves in response to a loss of nodes, interference, changing traffic conditions, etc. Such changes may require changing the frequency of operation of one or more links in the network. In networks with a single backhaul radio, a whole sub-tree rooted at a gateway node may have to change frequency. Changing channels, however, presents a risk in terms of loss of connectivity when errors occur.